The present disclosure relates to brake systems for railroad freight cars, and in particular relates to a handbrake operating linkage for manually moving a brake lever that may usually be moved by a motor such as a pneumatic cylinder-and-piston assembly of an air brake system during train operation.
Brakes on a railroad freight car in a train are normally operated by an air brake system including one or more pneumatic cylinder-and-piston assemblies pushing on brake levers in linkages that force brake shoes against the wheels of the freight car. Manually operated, or handbrake, linkages are also provided in such brake systems so that the brakes can be applied when the air brake system is inoperative, such as when a car is not coupled into a train. Such handbrake linkages include brake rods arranged to be pulled by chains and connected through other chains to pull on the same brake levers, to apply the brakes by hand. A handbrake operating linkage, however, must be arranged so as not to hamper or hinder operation of the air brake system to move the brake lever to apply or release the brakes when the brakes are not being kept applied by the handbrake linkage.
In the past, various linkages have been used to interconnect a handbrake rod with a brake lever, but such previously used linkages have included undesirably expensive parts, or have required more than desired amounts of skilled labor for their assembly, or both. For example, some such linkages have required a pair of devises to connect the ends of a special chain including a pair of long links and several ordinary links between the long links, and both the devises and the special chains have been undesirably expensive to manufacture.
In other handbrake linkages, such a special length of chain has been replaced by ordinary chain and one clevis has been eliminated, but a special joiner link used to connect the chain to the remaining clevis is both undesirably costly to manufacture and requires an undesirably expensive amount of labor for its assembly.
What is desired, then, is a handbrake operating system including an easily assembled and relatively inexpensive linkage for connecting a brake rod to a brake lever.